Mast arm



Aug'.. 18, 1925.

N. C. HUSTED MAST ARM Filed Sept. 9r 1924 2 Sheets-Sheet l N: c. HUsTED vMAST ARM 2 sheets-sheet 2 Filed Sept. 9 ,"1924 Patented Ang. 1s, 1925.

UNITED STATES NORRIS QJ HUSTED, OF NILES, OHIG.

MAST ARM.

Application led September 9, 1924. Serial No. 736,690.

To all whom t may concern.'

Be it known that I, Nonnrs C. HUsTED, a citizen of the United States, and a resident of Niles, in the county of Trumbull and the State of Ohio, have made a new and useful Invention in Mast Arms, of which the following is a specification.

This invention relates to mast arms and more particularly to that type of mast arm which is used to support a lighting fixture in spaced relation to a pole or mast on which it is mounted.

Arms of this type usually include a boom, shaped so as to form an inclosed trackway, and areV provided with a trolley which s movable along the trackway and which :is adapted to support a lighting fixture.

The trolley is usually held at the outer end of the boom when in use. Means are provided for moving the trolley and its supporting xture inwardly along the trackway to the inner end of the boom adjacent the supporting pole when it is necessary to clean or renew the lighting xture or any part thereof so that such operation may be conveniently performed from the.

pole end of the boom.

In residential sections it is often necessary to cut away the limbs of trees or the like in order to make room for the lighting fixture at the outer end of the boom.

An object of this invention is to construct a mast arm of the above type having an improvedv mechanism for securing the trolley against movement at any desired point along the boom so as to do away with the necessity of disfiguring trees and the like. i

A further object is to construct a mast arm of the type set forth having an improved mechanism for moving the trolley back and forth along the trackway of the Y boom.

A still further object is to improve the mast arm structure disclosed in my copendthe accompanying drawings, in which Figure 1 is a side elevation of a mast arm constructed in accordance with this invention, showing the same in position upon the supporting mast or pole, Fig. 2 is a ,plan view of the structure shown in Fig.

1 Fig. 3 is a verticall longitudinal section of the inner half of the mast arm,

Fig. 4 is a bottom View of the structure shown in Fig. 3, part of the device being .shown in section, Fig. 5 is a vertical longitudinal section of the outer end of the mast arm and Fig. 6 is a vertical cross section ron the line 6-6 of Fig. 5.

In the illustrated embodiment of my in- Vlvention 'I have shown, for the purposes of illustration a sheet metal boom 10 having lower face.

The trolley is adapted to be driven or moved `along the inclosed trackway from one end of the boom to the other. The driving mechanism includes a sprocket chain 17 which is secured at one end to the trolley axle 18 which is nearest the supporting pole. From this axle the chainpasses rearwardly adjacent the .trackway 12 to a sprocket wheel 19 which is securedto a rotatable shaft 20 'near the inner end of the boom. The chain passes around the sprocket wheel 19 and outwardly along the upper edge of the boom to an idler roller 21fand thence back to the other axle 22 of the trolley. The sprocket wheel 19 may be rotated in either direction through the inedium of a crank handle 23 which is secured to a projecting end of the sprocket supporting shaft 20. Obviously rotation of the sprocket wheel 19 will move the trolley along the inclosed trackway through the medium of the driving chain 17.

The shaft 20 extends through slots 24 and 25 formed in opposite sides of the Vboom and it is adjustable in the slots lengthwise of the boom through the medium of a substantially U-shaped bracket 26, the

arms of which rotatably receive the shaft 20 on opposite sides of the sprocket wheel 1S). A reach or tension rod 27 is secured to the bracket 26 and extends rearwardly along the inside of theA1 boom. The rear end of the tension rod is screw threaded and extends beyond the inner end of the boom, passing through openings 23 and 29 formed in the opposite legs of a U-shaped spring 3() which is rigidly mounted on that end of the boom 10, see Figs. 1 and 3. A wing-nut 31 or any similar device is threaded to the outer end of the tension rod and seats upon the U-shaped spring 30. Obviously rotation of the nut varies the outward pressure ofthe spring 3() upon the tension rod and this in turn varies the tension of the sprocket roller 19 upon the .chain 17. This structure enables sufficient tension to be applied to the chain to prevent the lower pass thereof from sagging below the hollow boom, so that the entire mechanism is inclosed within the boom and protected from the elements.

W hen the trolley is inthe desired position Ait is locked in place by securing the crank arm 23 against movement. The outer end of the crank-arm is provided with a hinged handle 32 which can be moved either to operative position as shown in Fig. 2 or to inoperative locking position as shown in Fig. 4. The means for locking the handle 32 and crank 23 againstmovement includes a hook like member 33 which is slidably mounted upon the tension rod 27 and projects downwardly therefrom through ythe slot formed in the bottom of the hollow boom. A catch 34 is pivoted to the hook 33 and is provided with a locking finger 35 for preventing the handle 32 from being unintentionally dis-placed when locked to the hook 33. The catch 34 has a projection 36 by means of which it may be moved to release-or lock the handle 32. In order to render the locking of the handle automatic, upon placing the same in the hook 33 the catch 34 is provided with a cam surface 37,

see Figs. 1 and 3, `so that as the handle 32 is inserted in the hook 33 it strikes the cam surface 37 and moves the catch upon its pivot in such a manner as to bring the locking finger 35 into the locking position shown in Fig, 3.

The boom 10 may be secured to the supporting pole 38 by means of a through bolt 39 extending through a perforation 40 formed in the inner end of the boom for that purpose. A brace arm 41 is provided to hold the boom against side sway. A stay rod 42 is secured to a supporting bracket 43 which may, if desired, be hung'upon the idler roller supporting shaft.

' lVhen in normal use the trolley 13 with its supported fixture is held against move- `ment at the outer end of the boom by securing the handle 32 in the locking hook 33. Then it is necessary to clean or repair the lighting fixture, this may be conveniently done from the pole end of the boom by removing the handle 32 from the lock, turning it to the position shown in Fig. 2 and rotating the sprocket wheel so as to move the trolley 13 inwardly along the inclosed trackway. Then the repair operation is finished the trolley is returned to its normal position by rotating the sprocket 19 in the reverse direction. 1f it is necessary to support the trolley at some point inwardly of the boom end so as to overcome the necessity of disiiguring trees, this may be done simply by locking the handle 32 in the hook 33 when the trolley has reached any desired position along the ing a hollow boom shaped so as to form an inclosed trackway, of a trolley movable along said trackway, a chain and sprocket for driving said trolley, a movable bracket within said boom connected to said sprocket, a spring secured to the pole end of said boom and a tension rod secured to said bracket and engaging said spring for applying tension to said chain.

2. The combination with a mast arm having a hollow boom shapedvso as to form an inclosed trackway, of a trolley movable along said trackway, a chain and sprocket for driving said trolley,I a movable bracket within said boom connected to said sprocket. a U-shaped spring secured to the pole end of said boom and a tension rod secured to said bracket and engaging said boom for applying tension to said chain and means for varying the pressure of said spring upon said rod.

v3. The combination with a mast arm having a hollow boom shaped so as to form an inclosed trackway, of a trolley movable along said trackway, means for driving said trolley including a crank arm, means for securing said crank arm against movement so as to lock said trolley in any desired position along said boom and means for locking said crank arm to said securing means.

4. rl`he combination with a mast arm having a hollow boom shaped so as to form an inclosed trackway, of a trolley movable along said trackway, means for driving said trolley including a crank arm, a handle hinged to said crank arm, a hook adapted to cooperate with said handle so as to secure said crank arm against movement and means for locking said handle in engage-- ment with said hook 5. The combination With a mast arm having a hollow boom shaped so as to form an inclosed trackway, of a trolley movable along` said trackvvay, means for driving said trolley including a crank arm, a handle hinged to said crank arm, a hook adapted to cooperate With said handle so as to secure said crank arm against movement and means operated by insertion or' said handle in said hook for locking it thereto.

6. The combination with a mast arm having a hollow boom shaped so as to form an inclosed trackWay of a trolley movable along said trackway, a sprocket and chain for driving said trolley, means including a tension rod for moving said sprocket so as to tension said chain, a crank arm for rotating said sprocket so as to move said trol* ley along said boom, a handle hinged to said crank arm and a hook depending,` from said tension rod and adapted to cooperate With said handle so as to secure said crank arm against movement.

7. The combination with a mast arm having a hollow boom shaped so as to form an inclosed trackWay, of a trolley movable along said trackway, a sprocket and chain for driving said trolley, means including aA tension rod for moving said sprocket so as to tension said chain, a crank arm for rotating said sprocket so as to move said trol ley along said boom, a handle hinged to said crank arm, a hook depending from said ten sion rod and adapted to cooperate with said handle so as to secure said crank arm agianst movement and means operated by insertion of said handle in said hook for locking it thereto.

In testimony whereof, I have hereunto subscribed my name this 6th day of September7 1924.

N'ORRIS C. HUSTED. 

